Well the achiles heel for Python is also deployment. The reason why we have so few applications is that each system has differences. RPM, DEB to other Distros or forget you just read this but (SystemD and not SystemD). With a flatpak you have a runtime and the runtime makes the hooks for the development.

Linux has a great tool for deploying different packages and it is hardly used. You build the package here and then it will rebuild it for other distros and systems. It could even make Windows and MacOS if they extend it. It is complex to do these things. https://build.opensuse.org/

With a flatpak or snap you just build the one package and it runs everywhere.

If I had a Euro for everytime I heard that, or some variation on that, I would have a lot of Euros

Package manager have nuances, and so have flatpak and snap installations.

Also, add Windows and macOS into the mix. Down the drain it is. It's basically what Docker was trying to get out of the way. Funny thing is that actually Go and Rust might be more the solution to the whole packaging dilemma that and packaging solution.